If you've not got any cable cutter but have a dremel (or other multitool) see if you have a diamond cut of disc ro buy one or a few of ebay for not too much. cuts both the outer types and the inners and leave an excellent finish
(quick pic search) and will look a bit like this
Save the grinding down of the ends to make them smooth or the pinching problem on brake outers.
Have a play, might be worth picking a cheap multitool up, as you can use it for other things as well
I can tell length for the frame, but the gear and brake length will depend on where you mount your levers, how high the bars are forks brakes etc...
Some people like them really long for some odd reason, I like mine neat and tight to avoid bends but long enough so there are no problems when turning tuning the bars fully (tweaked a bit for my preference and where cables rub)
Also don't forget to take into account ferrules when making them look neat, they make the cable out needed a touch shorter.